Self-Assembly of Porphyrin Arrays via Coordination to Transition

127.3 (m), 121.3 (q, J = 320 Hz, CF3SO3), 114.5 (s), 99.7 (s), 29.9 (PhP CH2), 18.4 (s, PhPCH2CH2). ...... Analytical Application of Oligopyrrole ...
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J. Am. Chem. Soc. 1999, 121, 2741-2752

2741

Self-Assembly of Porphyrin Arrays via Coordination to Transition Metal Bisphosphine Complexes and the Unique Spectral Properties of the Product Metallacyclic Ensembles Jun Fan,† Jeffery A. Whiteford,† Bogdan Olenyuk,† Michael D. Levin,† Peter J. Stang,*,† and Everly B. Fleischer‡ Contribution from the Departments of Chemistry, UniVersity of Utah, Salt Lake City, Utah 84112, and UniVersity of California, IrVine, California 92697 ReceiVed NoVember 17, 1998

Abstract: Self-assembly of predesigned angular and linear dipyridylporphyrin modules with bisphosphinecoordinated Pd(II) and Pt(II) angular and linear modules leads to cyclic porphyrin arrays containing two or four units and ranging in size from 15 to 39 Å. Multinuclear NMR spectra indicate high symmetry for these macrocycles. Restriction in rotation of trans-DPyDPP groups around the axis defined by the terminal metalnitrogen bonds distorts the symmetry of the tetramers, but the rotation is unrestricted at elevated temperatures. Chiral metal triflates containing R(+)- or S(-)-BINAP phosphines promote formation of enantiomeric macrocycles with a puckered geometry. CD spectra of the chiral macrocycles reveal a strong exciton coupling between the porphyrin chromophores in the tetramers. Emission spectra reveal moderate fluorescence quenching of the dipyridylporphyrin fluorophores upon treatment with metal triflates and concomitant incorporation into the macrocycles.

Introduction A significant amount of practical insight has been gained and correlated to natural chromophores by designing and comparing light harvesting porphyrin arrays and aggregates to monoporphyrin systems.1 Various molecular devices based on oligoporphyrins have recently been engineered and prepared, such as artificial photosynthetic systems,2 photoinduced picosecond molecular switches,3 optoelectronic gates,4 fluorescence quenching sensors,5 photonic wires,6 and cancer therapy agents.7 The porphyrin array architectures reported to date include linear chains,7,8 cyclic oligomers,9 squares,10 sheets and tapes,11 stars,12 †

University of Utah. University of California, Irvine. (1) For a comprehensive monograph, see: The Porphyrins; Dolphin, D., Ed.; Academic: New York, 1978. (2) (a) Wasielewski, M. R. Chem. ReV. 1992, 92, 435. (b) Gust, D.; Moore, T. A.; Moore, A. L. Acc. Chem. Res. 1993, 26, 198. (c) Harriman, A.; Sauvage, J.-P. Chem. Soc. ReV. 1996, 41. (d) Van Patten, P. G.; Shreve, A. P.; Lindsey, J. S.; Donohoe, R. J. J. Phys. Chem. B 1998, 102, 4209. (3) Gosztola, D.; Niemczyk, M. P.; Wasielewski, M. R. J. Am. Chem. Soc. 1998, 120, 5118. (4) Wagner, R. W.; Lindsey, J. S.; Seth, J.; Palaniappan, V.; Bocian, D. F. J. Am. Chem. Soc. 1996, 118, 3996. (5) De Silva, A. P.; Gunaratne, H. Q. N.; Gunnlaugsson, T.; Huxley, A. J. M.; McCoy, C. P.; Rademacher, J. T.; Rice, T. E. Chem. ReV. 1997, 97, 1515 and references therein. (6) Wagner, R. W.; Lindsey, J. S. J. Am. Chem. Soc. 1994, 116, 9759. (7) (a) Sousa, C.; Maziere, C.; Maziere, J. C. Cancer Lett. 1998, 128, 177. (b) deVree, W. J. A.; Essers, M. C.; Sluiter, W. Cancer Res. 1997, 57, 2555. (c) Jasat, A.; Dolphin, D. Chem. ReV. 1997, 97, 2267. (8) (a) Taylor, P. N.; Wylie, A. P.; Huuskonen, J.; Anderson, H. L. Angew. Chem., Int. Ed. Engl. 1998, 37, 986. (b) Nishino, N.; Wagner, R. W.; Lindsey, J. S. J. Org. Chem. 1996, 61, 7534. (c) Wagner, R. W.; Johnson, T. E.; Lindsey, J. S. J. Am. Chem. Soc. 1996, 118, 11166. (d) Osuka, A.; Tanabe, N.; Zhang, R. P.; Maruyama, K. Chem. Lett. 1993, 9, 1505. (e) Hammel, D.; Erk, P.; Schuler, B.; Heinze, J.; Mu¨llen, K. AdV. Mater. 1992, 4, 737. (9) (a) Vidal-Ferran, A.; Clyde-Watson, Z.; Bampos, N.; Sanders, J. K. M. J. Org. Chem. 1997, 62, 240. (b) Anderson, S.; Anderson, H. L.; Sanders, J. K. M. J. Chem. Soc., Perkin Trans. 1 1995, 2255. ‡

rosettes,13 dendrimers,14 and others.15 The porphyrin oligomers have been synthesized by either covalent attachment of the monomers3,4,7-9,10b,14 or methods of self-assembly.10a,c-13,15 Porphyrin arrays consisting of up to nine units have been reported.11 Nevertheless, the challenge remains for the preparation of new porphyrin-containing oligomers with well-defined structure and properties, since the optimal molecular arrangement for various applications has yet to be realized. Moreover, we have found no reports of chiral porphyrin arrays with more than two units.16 Preparation of the porphyrin arrays in high yields and significant quantities is still problematic. One of the major obstacles for porphyrin derivatives is low solubility, which complicates scale-up and characterization of the products.1 In (10) (a) Drain, C. M.; Lehn, J. M. J. Chem. Soc., Chem. Commun. 1994, 2313. (b) Wagner, R. W.; Seth J.; Yang, S. I.; Kim, D.; Bocian, D. F.; Holten, D.; Lindsey, J. S. J. Org. Chem. 1998, 63, 5042. (c) Slone, R. V.; Hupp, J. T. Inorg. Chem. 1997, 36, 5422. (11) Drain, C. M.; Nifiatis, F.; Vasenko, A.; Batteas, J. D. Angew. Chem., Int. Ed. Engl. 1998, 37, 2344. (12) Yuan, H.; Thomas, L.; Woo, L. K. Inorg. Chem. 1996, 35, 2808. (13) Drain, C. M.; Russell, K. C.; Lehn, J.-M. Chem. Commun. 1996, 337. (14) Xu, Z.; Moore, J. S. Acta Polym. 1994, 45, 83. (15) (a) Alessio, E.; Macchi, M.; Heath, S.; Marzilli, L. G. Inorg. Chem. 1997, 36, 5614. (b) Alessio, E.; Macchi, M.; Heath, S.; Marzilli, L. G. J. Chem. Soc., Chem. Commun. 1996, 1411. (c) Kobuke, Y.; Miyaji, H. Bull. Chem. Soc. Jpn. 1996, 69, 3563. (d) Stibrany, R. T.; Vasudevan, J.; Knapp, S.; Potenza, J. A.; Emge, T.; Schugar, H. J. J. Am. Chem. Soc. 1996, 118, 3980. (e) Tamiaki, H.; Miyatake, T.; Tanikaga, R.; Holzwarth, A. R.; Schaffner, K. Angew. Chem., Int. Ed. Engl. 1996, 35, 772. (f) Amabilino, D. B.; Dietrich-Bucheker, C. O.; Sauvage, J.-P. J. Am. Chem. Soc. 1996, 118, 3285. (g) Rao, T. A.; Maiya, B. G. J. Chem. Soc., Chem. Commun. 1995, 939. (h) Anderson, S.; Anderson, H. L.; Sanders, J. K. M. Acc. Chem. Res. 1993, 26, 469. (16) For examples of chiral self-assembled macrocycles see: (a) Mu¨ller, C.; Whiteford, J. A.; Stang, P. J. J. Am. Chem. Soc. 1998, 120, 9827. (b) Stang, P. J.; Olenyuk, B. Angew. Chem., Int. Ed. Engl. 1996, 35, 732. (c) Olenyuk, B.; Whiteford, J. A.; Stang, P. J. J. Am. Chem. Soc. 1996, 118, 8221.

10.1021/ja9839825 CCC: $18.00 © 1999 American Chemical Society Published on Web 03/11/1999

2742 J. Am. Chem. Soc., Vol. 121, No. 12, 1999 Scheme 1

Fan et al. Table 1. Size of Various Porphyrin Tetramers Based on MM2 Calculations building modules linear angular none 4L1 4L2

2A1 + 2A2 4A2 4A1

corresponding macrocycles

diagonal (Å)

side (Å)

20-23, 29, 30 12-19, 26-28 24, 25

15 29 39

12 20 24

Scheme 2

this paper, we describe the preparation of well-defined, highly soluble, readily available, macrocyclic arrays of two or four pyridyl-substituted porphyrins by self-assembly with bisphosphine-coordinated transition metal triflates.17 We have synthesized achiral and chiral cyclic arrays and studied their structure and properties by NMR, UV, emission, and CD spectroscopic techniques. Results and Discussion Design of Macrocycles. The self-assembly of rigid macrocycles requires well-defined, geometrically templated, building block precursors.18 Specifically, the assembly of square-shaped arrays requires four preprogrammed, 90° angular modules, which may be supplemented by four linear modules. Di(4′pyridyl)porphyrins substituted in positions 5 and 10 or 5 and 15 (1-6) can serve as the angular or linear building blocks, respectively. Square-shaped arrays of three types have been prepared based on the di(4′-pyridyl)porphyrins (Scheme 1). In the smaller macrocycles two 5,10-di(4′-pyridyl)porphyrins (1, 2, modules A1) alternate with two transition metal-based angular units A2 (7-10). 5,15-Di(4′-pyridyl)porphyrins (3-6) are used as the linear modules L1 spanning four angular units A2. Finally, four porphyrin-containing angular blocks A1 have been used to connect four platinum-terminated linear modules L2. Both free base porphyrin (1, 3, and 5) and zinc porphyrin derivatives (2, 4, and 6) are employed as the modules A1 and L1. Bistriflates of 1,3-bis(diphenylphosphino)propane (dppp), 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP), dpppPd(II) (7), dpppPt(II) (8), and R(+)-, S(-)-BINAP-Pd(II) (9 and 10) have been used as precursors for the angular units A2, and 1,4-bis-[trans-Pt(PEt3)2(OTf)]benzene (11) has been used as the precursor for the linear units L2. The geometrical parameters of the molecular (17) For a preliminary communication see: Stang, P. J.; Fan, J.; Olenyuk, B. J. Chem. Soc., Chem. Commun. 1997, 1453. (18) (a) Olenyuk, B.; Fechtenko¨tter, A.; Stang, P. J. J. Chem. Soc., Dalton Trans. 1998, 1707. (b) Stang, P. J.; Olenyuk, B. Acc. Chem. Res. 1997, 30, 502 and references therein. (c) Fujita, M. J. Synth. Org. Chem., Jpn. 1996, 54, 953 and references therein.

squares, as evaluated by molecular modeling (modified MM2),19 are listed in Table 1. Synthesis and General Properties of Macrocycles. Achiral cyclic tetramers 12-19 were obtained by reacting bistriflates of dpppPd(II) or dpppPt(II) (7 and 8) with 5,15-di(4′-pyridyl)10,20-diphenylporphyrin (trans-DPyDPP) (3), 5,15-di(4′-pyridyl)-3,7,13,17-tetramethyl-2,8,12,18-tetrahexylporphyrin (transDPyTTP) (5), and their zinc-containing analogues 4 and 6 (Scheme 2). The triflates 7 and 8 were also reacted with 5,10di(4′-pyridyl)-15,20-diphenylporphyrin (cis-DPyDPP) (1) and cis-ZnDPyDPP (2) to yield the smaller macrocycles 20-23 (Scheme 3). Larger macrocycles 24 and 25 resulted from the reaction between the angular porphyrin precursors 1 and 2 and 1,4-bis[trans-Pt(PEt3)2(OTf)]benzene (11, Scheme 4). The chiral macrocycles 26 and 27 were formed in good yields by the reaction of trans-DPyDPP (3) with pure R (+)- or S (-)BINAP-Pd(II) bistriflates 9 and 10 (Scheme 5). trans-ZnDPyDPP (4) yielded the tetramer 28 upon reaction with 9. Reaction of cis-DPyDPP (1) with the triflates 9 and 10 gave access to the chiral dimer macrocycles 29 and 30, respectively (Scheme 6). (19) (a) MM2 single point calculations and geometry optimization was performed with CS Chem3D Pro, Version 3.5.1, CambridgeSoft Corporation, 875 Massachusetts Avenue, Cambridge, MA 02139. (b) ESFF potential set geometry optimization was performed with INSIGHT II (97.0) and Discover 3, BIOSYM. The dielectric constant was set to 8.0.

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Scheme 3

Scheme 5

Scheme 4

R-pyridyl protons in the 1H NMR spectra, while the metalcontaining reagent has a distinctive signal for the bisphosphine ligands in the proton-decoupled 31P NMR spectra. Excess of either reagent can be quenched with the other reagent without significant effect on the yield. When the correct stoichiometry is achieved, the corresponding signals of the starting materials disappear. The formation of the respective macrocycle is complete when the line width of the 31P{1H} NMR signal reaches its minimum. Dichloromethane is the preferred solvent in most cases, but acetone or mixtures of chloroform and methanol are required for the zinc-containing porphyrins 2, 4, and 6 because of low solubility in dichloromethane. Longer reaction times and higher temperatures are usually needed for the completion of the reactions involving zinc-containing porphyrin derivatives, and somewhat lower isolated yields are observed in these reactions. Formation of the dimer macrocycles 20-23 proceeds faster than that of the tetramer macrocycles. The purple-red microcrystalline macrocycles precipitate out of the reaction mixture upon addition of diethyl ether. Analytically pure samples are obtained by redissolving the assemblies in the original solvent and recrystallizing them upon slow infusion of diethyl ether. Interestingly, all macrocycles are more soluble than the precursor porphyrins alone. Presumably, the positive charge of the macrocycles and the arrangement of the phosphine ligands is such that they project out of the plane defined by the corners of the macrocycles, and prevent intermolecular stacking. This makes the crystal packing less thermodynamically favorable, and, thus, increases the solubility of the macrocycles. In this respect, the bisphosphine-coordinated Pd(II) and Pt(II) angular modules have solubility advantages over the analogous neutral transition metal chlorides used previously.10a,11 The higher solubility of the charged porphyrin oligomers allows one to carry out self-assembly on a preparative scale at a higher concentration without precipitation of the intermediates.

Since both reagents in these reactions contain variable amounts of water, it is necessary to monitor the stoichiometry of the reagents by NMR while preparing these assemblies. The pyridyl-containing reagent has a characteristic signal for the

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Scheme 6

The tetramers are stable below 240 °C, while the dimers decompose when heated above 350 °C. The decomposition temperature of the Pt-based macrocycles is 30-40 °C higher than those of their Pd-based analogues. Additionally, the macrocycles are somewhat hydroscopic in the solid state and light sensitive in solution.

Figure 1. Assignment of the aromatic region of the 1H NMR spectrum of tetramer 13, 5.5 × 10-3 M in acetone-d6 at ambient temperature.

trans-Dipyridylporphyrin Tetramers. The macrocycles 1215 have complex, but similar 1H NMR spectra. The assignment of the aromatic region of the 1H NMR spectrum of 13 in acetone-d6 (Figure 1) was based on a 1H-1H COSY NMR spectrum and by comparison with the spectra of other dppp chelated macrocycles. The doublets at δ 9.7 and 8.4 ppm are due to the R- and β-protons of the pyridyl moieties. The signals of the R-protons in 12-15 are significantly shifted downfield compared to those in the parent porphyrin due to coordination of the pyridyl group to a metal.10a,c,12 The four signals between δ 8.1 and 9.1 ppm are attributed to the porphyrin-bound protons (Hp and Hp′). The number of these signals is twice as large as the number of the corresponding signals in the parent transDPyDPP (3). The doubling of the number of signals is caused by the orientation of the porphyrin rings in the macrocycle such that half of the protons (Hp′) are located inside of the macrocycle, while the other half (Hp) are located outside of the macrocycle. The intense signals at δ 8.3 and 7.8 ppm are assigned to the phenyl-bound protons of the dppp groups (HL). Finally, the four signals at δ 8.3,20 8.0, 7.0, and 6.1 ppm are due to the protons attached to the phenyl groups in positions 10 and 20 on the porphyrin rings (Hph and Hph′). As in the case of the signals of the porphyrin-bound protons, the large number of signals from the phenyl-bound Hph and Hph′ is due to inequivalent phenyl groups located inside and outside of the macrocycle, respectively.

These spectroscopic data are in accord with the results of molecular modeling of the structure of tetramers 12-15 and with studies of restricted rotation in pyridine-transition metal complexes.21 At the optimized geometries (modified MM2)19 for the tetramers, the pyridyl groups are perpendicular to the coordination plane of the metals and the plane of the porphyrin rings. This forces the porphyrin rings to be nearly coplanar with each other resulting in a planar macrocycle. Rotation around the metal-nitrogen bonds and the bonds between the pyridyl and porphyrin moieties is slow at ambient temperature on the NMR time scale, and this causes splitting of the signals and/or broadening of the lines in the spectra.16c The line widths and the splitting patterns vary with solvent, temperature, and the coordinated metal. In less polar solvents (e.g. chloroform as compared to acetone) the signals due to the pyridyl-bound R-protons and the phenyl-bound dppp protons are broader, and the splitting between the signals of the porphyrin-bound protons is larger. This splitting is reduced at elevated temperatures. In the dpppPd-based tetramer 12, the upfield signals, attributed to the phenyl-bound protons of the trans-DPyDPP moiety (Hph and Hph′), coalesce around 60 °C in CDCl3 solution. For the dpppPtbased tetramer 13 the effect of temperature is less pronounced, and the coalescence cannot be reached below the boiling point of CDCl3 at ambient pressure. Restriction in rotation around the metal-nitrogen bonds is relaxed at elevated temperature and in more polar solvents. The fact that the ligands rotate faster in the Pd-based macrocycles compared to the Pt-based analogues is in accord with the previous studies of such rotation.21 The 31P{1H} NMR spectra of each of the tetramers 12 and 14 consist of one singlet at ambient conditions. The 31P{1H} NMR spectra of tetramers 13 and 15 are similar to those of 12 and 14, except that they contain platinum satellites due to the 195Pt-31P spin-spin coupling. Compared to the 31P{1H} NMR

(20) This signal overlaps in the 1D 1H NMR spectrum with a signal of dppp phenyl-bound protons. It has been assigned based on the 1H-1H COSY NMR spectrum of 13.

(21) (a) Fuss, M.; Siehl, H.-U.; Olenyuk, B.; Stang, P. Organometallics 1999, 18, in press. (b) Stang, P. J.; Olenyuk, B.; Arif, A. M. Organometallics 1995, 14, 5281.

NMR Spectra

Self-Assembly of Porphyrin Arrays

Figure 2. 31P{1H} NMR spectra of the tetramer 26 in a CD3NO2 solution at various temperatures.

signals of the bistriflates 7 and 8, the tetramer signals are shifted upfield by ∼10 ppm, indicative of the coordination of the nitrogen lone pair to the transition metal.22 The singlet in the spectrum of 13 splits into two below 0 °C in CDCl3. The splitting of the signal is most likely due to the slow interconversion of conformers with inequivalent phosphorus nuclei. The conformers may be formed in two ways. If all four metal corners are in one plane, the conformers will differ by the mutual orientation of the porphyrin moieties with their parts inside and outside of the macrocycle above or below the plane. If the geometry of the cyclic tetramers is puckered, the conformers will differ by the relative arrangement of the porphyrin cores to the puckering angle. In the former case, the coalescence of the 31P{1H} NMR signals in the tetramers corresponds to the unfreezing of the restricted rotation of the porphyrin modules so that they can turn around the coplanar arrangement, but still cannot rotate freely around the axis defined by the metals. In the latter case, coalescence of the signal suggests unfreezing of the puckering motion in the macrocycles. The 31P{1H} NMR spectra of the chiral phosphine containing tetramers 26, 27, and 28 consist of two signals. The major signal has an AB pattern, caused by the spin-spin coupling of two inequivalent 31P nuclei coordinated to the same metal. A less intense broad signal appears close to the center of the AB pattern of the major signal. In the case of the macrocycle 26, these two signals collapse into one sharp singlet at ca. 60 °C in a CD3NO2 solution (Figure 2). The changes are reversible upon cooling. This observation allows the assignment of the AB pattern to the most favorable macrocycle conformer, while the minor (22) Stang, P. J.; Cao, D. H.; Saito, S.; Arif, A. M. J. Am. Chem. Soc. 1995, 117, 6273.

J. Am. Chem. Soc., Vol. 121, No. 12, 1999 2745 signals are presumably due to one or more other conformers. Analysis of the possible mutual arrangements of the porphyrin modules in the tetramers (Figure 3) shows that only two conformers possess the required symmetry to give the experimentally observed 31P{1H} NMR spectrum. A dome-shaped structure I, where the four transition metals define the plane, is in the C4 symmetry point group (Figure 3a) while the puckered configuration II is defined as D2 (Figure 3b). In the latter structure the porphyrin rings are oriented such that two C2 symmetry axes are passing through four meso carbon atoms of the opposite side rings. Each structure contains four equivalent bisphosphine ligands, with a pair of inequivalent phosphorus nuclei at each metal center. Molecular modeling (modified MM2 and ESFF)19 suggests that structure II has a lower energy than structure I. Furthermore, no local minimum has been found for a structure with C4 symmetry. Geometry optimization (ESFF) yielded several local minima (e.g, III, Figure 3c) with structures similar to II. All these structures have the same puckered geometry but differ in the relative orientation of the porphyrin rings, which are con- or disrotated by about 30° around the PdPd axis. This relieves some strain from steric interaction between the porphyrin-bound phenyl groups. Apparently, structure II is the average of the less symmetric structures with local minima, which is in agreement with the 31P NMR data. Furthermore, the puckered structure is also favored by the BINAP-coordinated metal corners since they prefer the pyridyl ligand planes with a dihedral angle less than 90°. Interestingly, the coalescence of the signals in the 31P NMR spectra of the BINAP-containing tetramer 26 occurs at a much higher temperature than that of the analogous dppp-containing tetramer 13. Assuming the puckered structure II for the tetramer 26, the difference in the coalescence temperatures can be explained by a difference in the mechanism by which the macrocycles 13 and 26 increase their symmetry, or by a different barrier to puckering in the corresponding macrocycles. cis-Dipyridylporphyrin Dimers and Tetramers. The spectra of the cis-DPyDPP dimers 20-23 and tetramers 24 and 25 are similar to those of the trans-DPyDPP tetramers 12-15. The signals in the 1H NMR spectra of the dimers 20-23 are narrower compared to those of 12-15, presumably due to the lack of conformational changes at ambient temperature on the NMR time scale. The 1H NMR spectra of the tetramers 24 and 25 are simpler than those of the dppp-containing macrocycles since they do not contain the signals from the dppp phenyl groups. The signals due to the pyridyl-bound protons in 24 and 25 are shifted upfield compared to those in the other macrocycles. The 31P{1H} NMR spectra of the macrocycles 20-23 consist of single signals, which indicates that all the phosphorus nuclei are equivalent. The signals are shifted upfield by ca. 15 ppm compared to those of the starting bistriflates 7 and 8 as a result of a strong coordination of the pyridyl groups to the transition metals. The 31P{1H} NMR spectra of the macrocycles 24 and 25 consist of a singlet with two symmetrical satellites. The singlet is shifted upfield by 4 ppm compared to that of the starting bistriflate. The 19F NMR spectrum of every individual macrocycle consists of one narrow singlet at around δ -77 ppm, which is characteristic for an uncoordinated triflate anion.23 Mass Spectrometry Fast atom bombardment mass spectrometry (FABMS) analysis of 20 and 21 gave M - OTf peaks of m/z 2716.5 and m/z 2895.8, respectively, with +1 charge states (i.e., separation of (23) Lawrance, G. A. Chem. ReV. 1986, 86, 17.

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Figure 3. (a) Structure I: Only meso-carbons of porphyrins and Pd atoms are shown. (b) Structure II: Only meso-carbons of porphyrins and Pd atoms are shown. (c) Structure III: Only meso-carbons of porphyrins and Pd atoms are shown.

peaks by 1 m/z unit) resulting from a loss of one triflate from a total of four. Also indicative of the proposed molecule were the isotopic distribution patterns which were very close to the calculated compositions of the species. The calculated and experimental isotopic distribution patterns of the platinum analogue 21 are shown in Figure 4. Although this technique has been successful in producing evidence for the smaller macrocycles 20 and 21 and several other examples,24 the upper molecular weight limit is approximately 4000-5000 amu. Alternatively, electrospray mass spectrometry (ESMS) has been successful in identifying the composition of larger aggregates and assemblies (5000-10000).25 Application of this technique to macrocycle 16 gave similar results to previously reported examples studied by ESMS. The observation of the +4 species (1525.3 m/z) resulting from the loss of four triflate counterions (from a total of eight) and the isotopic distribution consistent with the theoretical isotopic envelope confirmed the composition of macrocycle 16. Absorption and Emission Spectra The maxima of the Soret and Q-bands, characteristic for the porphyrin chromophores,26 are red-shifted by 8-12 nm in the macrocycles 12-30 as compared to those of the starting porphyrins. This shift is more pronounced for the Pt-containing macrocycles. Analogous but smaller shifts have been reported for Pt(II)- and Pd(II)-coordinated monopyridyl porphyrin derivatives.12 The Soret bands of the macrocycles 12-30 are broader compared to those of the starting porphyrins 1-6, which may be attributed to an intramolecular exciton coupling between the (24) Whiteford, J. A.; Rachlin, E. M.; Stang, P. J. Angew. Chem., Int. Ed. Engl. 1996, 35, 2524. mass spec ref 4000-5000 mw limit. (25) Manna, J.; Kuehl, C. J.; Whiteford, J. A.; Stang, P. J.; Muddiman, D. C.; Hofstadler, S. A.; Smith, R. D. J. Am. Chem. Soc. 1997, 119, 11611. mass spec ref 5000-10000 mw limit. (26) Gouterman, M. In The Porphyrins. Vol. 3, Physical Chemistry, Part A; Dolphin, D., Ed.; Academic: New York, 1978.

Figure 4. Experimental (top) and calculated (bottom) isotopic distribution pattern of (M-OTf)+ for 21.

porphyrin chromophores in the macrocycles. The extinction coefficient per porphyrin unit decreases upon formation of almost every macrocycle. The only exception is trans-ZnDPyDPP (4). Its absorption in solution is depressed ( 79 000 mol-1 × cm-1 at λ 420 nm) compared to other similar porphyrins ( ca. 350 000 mol-1 × cm-1), presumably due to an extensive intermolecular coordination of the pyridyl groups to the zinc

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J. Am. Chem. Soc., Vol. 121, No. 12, 1999 2747

Figure 5. Absorption spectra of reaction mixtures of cis-DPyDPP (1) and dpppPd(OTf)2 (7), 5 × 10-6 M solution in CH2Cl2 at ambient temperature.

atoms.27 The molar absorptions of the trans-ZnDPyDPPcontaining macrocycles 13 and 15, however, are comparable to those of the similar macrocycles 12, 14, and 16-30. Thus, we observe a significant increase in the extinction coefficient per porphyrin unit upon incorporation of trans-ZnDPyDPP in the macrocycles 13 and 15. An interesting observation is that the porphyrins incorporated in the macrocycles do not possess a shoulder to their Soret band due to the B(0-1) transition.26 The only exceptions are the macrocycles 26 and 27 with the BINAP-Pd(II) corners. If an excess of the metal-containing reagent is present in the reaction mixture, a distinct shoulder to the Soret band of a porphyrin at longer wavelengths (usually ca. 460 nm) is observed (Figure 5). A steady decrease in fluorescence is observed upon titration of trans-DPyDPP or cis-DPyDPP solutions with solutions of dppp-metal triflates in CH2Cl2. An overall 30-60% drop in fluorescence of the porphyrins is observed upon formation of the macrocycles. The fluorescence of the macrocycles is suppressed even further upon addition of excess of the dpppmetal triflates. The decrease in fluorescence is more pronounced upon addition of dpppPt(II) than dpppPd(II) triflate. This observation is in accord with an assumption that the heavyatom effect is the major contributor to the fluorescence quenching.28 CD Spectra of Macrocycles Containing Chiral Bisphosphines A striking feature of the CD spectra of the tetramers 26 and 27 is the bisignate curve (positive and negative components) between 400 and 450 nm (Figure 6). It is probably due to exciton coupling between two or more porphyrin chromophores of the macrocycle.29 The apparent Davydov splitting29,30 is 10 nm. The amplitude of the splitting is quite impressive: ∆ ) 1800 L × mol-1 × cm-1. This amplitude is inversely proportional to the square of the interchromophore distance31 and proportional to the square of the extinction coefficients.32 An extremely high (27) (a) Hunter, C. A.; Hyde, R. K. Angew. Chem., Int. Ed. Engl. 1996, 35, 1936. (b) Fleischer, E. B.; Shachter, A. M. Inorg. Chem. 1991, 30, 3763. (28) Klessinger, M.; Michl, J. Excited States and Photochemistry of Organic Molecules; VCH: New York, 1995. (29) Harada, N.; Nakanishi, K. Circular Dichroic Spectroscopy; University Science Books: Mill Valley, CA, 1983. (30) (a) Harada, N.; Nakanishi, K. Acc. Chem. Res. 1972, 5, 257. (b) Davydov, A. S. Theory of Molecular Excitons McGraw-Hill: New York, 1962. (31) Harada, N.; Chen, S.-M.; Nakanishi, K. J. Am. Chem. Soc. 1975, 97, 5345. (32) Heyn, M. P. J. Phys. Chem. 1975, 79, 2424.

Figure 6. CD and UV-vis spectra of the tetramer 26 (solid line) and 27 (dashed line), 1.1 × 10-6 M solution in CH2Cl2 at ambient temperature.

extinction coefficient of the porphyrin chromophores provides for a very strong exciton coupling in the macrocycles.33 However, even taking into account the short interchromophore distances of ca. 14 Å between the adjacent porphyrin cores and ca. 21 Å between the porphyrin cores opposite one another, the observed magnitude of the splitting may be explained only by a cooperative interaction between several porphyrin chromophores. Three types of coupling interactions may exist between the four porphyrin chromophores in 26 and 27: (a) four “adjacent” porphyrin couplings (pairs of porphyrins attached to the same transition metal corner), (b) two “opposing” porphyrin couplings (porphyrins on opposing sides of the macrocycle), and (c) a combination of a and b. Examination of structure II reveals that both the “adjacent” and the “opposing” pairs of porphyrin chromophores are in the same chiral environment of the BINAP ligands. This is in accord with the signs of the first and the second Cotton effects observed in the CD spectrum for the Soret band of the macrocycles 26 and 27, as well as with the large magnitude of the splitting due to mutual cooperativity. The macrocycles 26 and 27 are enantiomers, hence their CD spectra are mirror images of each other. No circular dichroism is observed for the Soret band of the zinc-containing tetramer 28 presumably because of the high symmetry (D4h) of the zinc porphyrin chromophore.26 Circular dichroism ( 300 at λ 420 nm) without chiral exciton coupling is observed for the Soret band of the macrocycles 29 and 30. This fact suggests that the two porphyrin cores are coplanar, and the consequent coplanarity of the transition moments of (33) Matile, S.; Berova, N.; Nakanishi, K.; Fleischhauer, J.; Woody, R. W. J. Am. Chem. Soc. 1996, 118, 5198.

2748 J. Am. Chem. Soc., Vol. 121, No. 12, 1999 the chromophores prevents the coupling from being observed.29 The dimers 29 and 30 are enantiomers and also give antipodal Cotton effects, respectively. Conclusions Macrocyclic assemblies, containing two or four porphyrin units, are readily obtained on a preparative scale via selfassembly with use of Pd(II)- or Pt(II)-containing auxiliary modules. The bisphosphine ligands coordinated to transition metals provide for an enhanced solubility of the macrocycles. The porphyrin cores are not coplanar when used as parts of the linear modules in the tetramers 12-19. The barrier to rotation of the trans-DPyDPP moiety around the axis defined by the two metal-nitrogen bonds in the nonchiral tetramers depends on the type of transition metal used in the assembly and on the solvent. Two stages of unfreezing of the conformational motion are distinguished by NMR spectroscopy: initially the macrocycles adopt a coplanar arrangement, and at a high temperature the full rotation of the rings becomes fast on the NMR time scale. Chiral macrocycles are formed upon employment of the BINAP-Pd(II) angular building block. The chiral tetramers have a puckered structure of D2 symmetry at ambient temperature. The porphyrin chromophores in the enantiomeric dimers 29 and 30 and the enantiomeric tetramers 26 and 27 show strong circular dichroism around 420 nm. Cooperative coupling of four excitons in the tetramers 26 and 27 leads to Davydov splitting with a very high amplitude. The high solubility and ease of synthesis of self-assembled porphyrin macrocycles, based on Pt(II) and Pd(II) phosphine bistriflates, provides tetramers that are excellent ensembles for the study of porphyrin exciton coupling interactions and induced circular dichroism (ICD). Experimental Section General Methods. All reactions were conducted under a dry nitrogen atmosphere following Schlenk techniques, although the products may be handled in air. IR spectra were recorded on a Mattson Polaris FTIR spectrometer. UV-vis spectra were obtained with use of a HewlettPackard 8452A UV-vis spectrophotometer. Circular dichroism (CD) spectra were recorded on an Aviv 62ADS CD spectrometer. Optical rotations were measured on a Perkin-Elmer 241MC polarimeter. NMR spectra were recorded on a Varian Unity-300, Varian XL-300, or Varian VXR-500 spectrometer. The 1H NMR spectra were recorded at 300 or 500 MHz, and chemical shifts are reported relative to internal TMS δ 0.0 ppm or to the signal of a residual protonated solvent: CDHCl2 δ 5.32 ppm, CHCl3 δ 7.27 ppm, or (CD3)CO(CD2H) δ 2.05 ppm. The 13C{1H} NMR spectra were recorded at 75 or 125 MHz, and chemical shifts are reported relative to CD2Cl2 δ 54.00 ppm or CDCl3 δ 77.23 ppm. The 19F NMR spectra were recorded at 282 MHz and chemical shifts are reported relative to external CFCl3 δ 0.0 ppm. The 31P{1H} NMR spectra were recorded at 121 or 202 MHz, and chemical shifts are reported relative to external 85% aqueous H3PO4 δ 0.0 ppm. The signals in 1H NMR due to water are omitted. Elemental analyses were performed by Atlantic Microlab Inc., Norcross, GA. Melting points were obtained with a Mel-Temp capillary melting point apparatus and were not corrected. Mass spectra of 20 and 21 were obtained with a Finnigan MAT 95 mass spectrometer with a Finnigan MAT ICIS II operating system under positive fast atom bombardment (FAB) conditions at 20 keV. 3-Nitrobenzyl alcohol was used as a matrix in CHCl3 as a solvent, and polypropylene glycol and cesium iodide were used as a reference for peak matching. Larger macrocycle (>5000 amu) 16 was analyzed with a Micromass Quatro II with ionization performed under electrospray conditions (flow rate 7.7 µL/min; capillary voltage 3.0 kV; cone 27 V; Extractor 12 V). About 15 individual scans were averaged for the mass spectrum. The calibration of the mass range 1003000 amu was done with a 1:1 mixture of a 2-propanol-water solution of NaI (2 µg/µL) and CsI (0.01 µg/µL). Samples were prepared as 10 pg/µL solutions in acetone just prior to the analysis.

Fan et al. Materials. Commercial reagents were ACS reagent grade or higher and were used without further purification. Methylene chloride was purified according to literature procedure34 and distilled over CaH2. Diethyl ether was purified according to literature procedure34 and distilled over Na/benzophenone. Methylene chloride and chloroform used for spectroscopic measurements were spectrophotometric grade. 3,3′-Dihexyl-4,4′-dimethyl-2,2′-dipyrrylmethane,35 cis-DPyDPP (1),27b trans-DPyDPP (3),27b dpppPd(OTf)2 (7),22 dpppPt(OTf)2 (8),22 Pd(R(+)BINAP)(OTf)2 (9),16c Pd(S(-)-BINAP)(OTf)2 (10),16c and 1,4-bis(transPt(PEt3)2(OTf))benzene (11)25 were prepared according to published procedures. cis-ZnDPyDPP (2). To a stirred solution of 100.0 mg (0.16 mmol) of 1 in a 70 mL of mixture of CHCl3 and MeOH (3:1) was added 356 mg (1.6 mmol) of Zn(OAc)2. The mixture was stirred and refluxed in the dark for 20 h. The solvent was removed in vacuo. The residue was washed with MeOH (3 × 20 mL). The product was dried in vacuo. Yield: 79 mg (73%). Mp > 400 °C dec. 1H NMR (300 MHz, CDCl3) δ 8.90 (s, 2H, H-17 and H-18), 8.76 (d, J ) 3.9 Hz, 2H, H-2 and H-13), 8.15 (m, 6H, H-3, H-12, and Ph Ho), 7.98 (s, 2H, H-7 and H-8), 7.73 (m, 6H, Ph Hm, Hp), 7.17 (br, s, 4H, py Hβ), 2.45 (s, 4H, py HR). 13C{1H} NMR (75 MHz, CDCl ) δ 150.9 (s), 150.4 (s), 148.7 (s), 148.1 3 (s), 143.0 (s), 134.7 (s), 132.9 (s), 132.7 (s), 130.8 (s), 130.6 (s), 129.1 (m), 127.8 (s), 126.7 (s), 122.5 (s). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 422 (537 000), 552 (17 000), 600 (7000). MS (CI) m/z 679.2 (100, M+). Anal. Calcd for C42H26N6Zn‚H2O: C, 72.26; H, 4.04; N, 12.04. Found: C, 71.79; H, 3.92; N, 11.85. trans-ZnDPyDPP (4). To a stirred solution of 30.0 mg (0.049 mmol) of 3 in a 40 mL mixture of CHCl3 and MeOH (3:1) was added 106.6 mg (0.49 mmol) of Zn(OAc)2. The mixture was stirred and refluxed in the dark for 10 h. The solvent was removed in vacuo. The residue was washed with MeOH (3 × 20 mL). The product was dried in vacuo. Yield: 34 mg (100%). Mp 360-362 °C dec. 1H NMR (300 MHz, CDCl3) δ 8.70 (d, J ) 3.9 Hz), 8.08 (m), 7.70 (m), 7.20 (br, s, 4H, py Hβ), 2.13 (s, 4H, py HR). 13C{1H} NMR (75 MHz, CDCl3) δ 152.2 (s), 150.5(s), 148.5 (s), 144.3 (m), 143.0 (s), 139.1 (s), 134.6 (6), 132.7 (s), 130.7 (s), 129.1 (s), 127.7 (s), 126.6 (s), 121.8 (s), 120.9 (s), 118.5 (s), 118.1 (s), 116.3 (m). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 418 (76 000), 548 (7000), 614 (4000). trans-DPyTTP (5). A solution of 380 mg (1.11 mmol) of 3,3′dihexyl-4,4′-dimethyl-2,2′-dipyrrylmethane, 120 mg (1.11 mmol) of 4-pyridinecarboxaldehyde, and 56.8 mg (0.3 mmol) of p-toluenesulfonic acid in 14 mL of methanol was stirred for 6 h in the dark at ambient temperature and for 16 h at 0 °C. Then, 531 mg (2.34 mmol) of 2,3dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) was added and the mixture was stirred in the dark for an additional 4 h. The precipitate was filtered and washed with methanol. The filtrate was evaporated and the residue was treated with a 10% aqueous solution of NaOH, then with water. The black solid was dissolved in CH2Cl2 and filtered through a short pad of silica gel and further purified by column chromatography with a mixture of CH2Cl2 and ethyl acetate (3:1) as eluent. Yield: 50 mg (12%). Mp 250-252 °C dec. 1H NMR (300 MHz, CD2Cl2, TMS) δ 10.28 (s, 2H, H-10 and H-20), 9.05 (d, J ) 5.7 Hz, 4H, py HR), 8.09 (d, J ) 6.0 Hz, 4H, py Hβ), 3.99 (t, J ) 7.8 Hz, 8H, porph-CH2-(CH2)4CH3), 2.53 (s, 12H, porph-CH3), 2.19 (m, 8H, porphCH2CH2-(CH2)2CH3), 1.74 (m, 8H, porph-(CH2)2CH2-(CH2)2CH3), 1.48 (m, 8H, porph-(CH2)3CH2-CH2CH3), 1.38 (m, 8H, porph-(CH2)4CH2CH3), 0.91 (t, J ) 7.2 Hz, 12H, porph-(CH2)5CH3), -2.42 (s, 2H, NH). 13C{1H} NMR (75 MHz, CD Cl , TMS) δ 150.8 (s, py C ), 149.2 (s, 2 2 γ py CR), 144.3 (s, porph C4), 144.2 (s, porph C1), 141.8 (s, porph C3), 135.6 (s, porph C2), 128.5 (s, py Cβ), 114.8 (s, porph C5-py), 97.7 (s, C10), 33.6 (s, porph-CH2), 32.2 (s, porph-CH3), 30.2 (s, hexyl CH2), 27.0 (s, hexyl CH2), 23.0 (s, hexyl CH2), 15.2 (s, hexyl CH2), 14.4 (s, hexyl CH3). IR (neat) 2930, 2854, 1590, 1462, 1286, 1129, 1068, 960, 759 cm-1. UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 292 (493 000), 406 (180 4000), 508 (186 000), 540 (87 000), 574 (87 000), 628 (36 000). MS (CI) m/z 857 (M+, 100). trans-ZnDPyTTP (6). To a stirred solution of 20.0 mg (0.023 mmol) of 5 in a 40 mL of mixture of CHCl3 and MeOH (3:1) was added 51.2 (34) Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory Chemicals; Pergamon Press: Oxford, 1988. (35) Bao, Z.; Chen, Y.; Yu, L. Macromolecules 1994, 27, 4629.

Self-Assembly of Porphyrin Arrays mg (0.23 mmol) of Zn(OAc)2. The mixture was stirred and refluxed in the dark for 3 h. The solvent was removed in vacuo. The residue was washed with MeOH (3 × 20 mL). The product was dried in vacuo. Yield: 17 mg (79%). Mp 284-286 °C dec. 1H NMR (300 MHz, CDCl3) δ 9.99 (s, 2H, H-10 and H-20), 3.81 (t, J ) 5.0 Hz, 8H, porphCH2-(CH2)4CH3), 2.04 (m, 8H, porph-CH2CH2-(CH2)3CH3), 1.66 (br, s, 20H, porph-CH3 and porph-(CH2)2CH2-(CH2)2CH3), 1.44 (m, 8H, porph-(CH2)3CH2-CH2CH3), 1.34 (m, 8H, porph-(CH2)4CH2-CH3), 0.86 (t, J ) 6.9 Hz, 12H, porph-(CH2)5CH3). 13C{1H} NMR (75 MHz, CDCl3, TMS) δ 152.7 (s, py Cγ), 146.5 (s, py CR), 146.1 (s, porph C4), 143.9 (s, porph C1), 136.4 (s, porph C3), 136.3 (s, porph C2), 127.8 (s, py Cβ), 114.9 (s, porph C5-py), 97.9 (s, C10), 33.6 (s, porph-CH2), 32.2 (s, porph-CH3), 30.3 (s, hexyl CH2), 27.0 (s, hexyl CH2), 23.0 (s, hexyl CH2), 15.3 (s, hexyl CH2), 14.4 (s, hexyl CH3). IR (neat) 2924, 1609, 1458, 1261, 1069 cm-1. UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 412 (342 000), 540 (20 000), 576 (11 000). MS (CI) m/z 919 (M+, 100). [Pd(dppp)(trans-DPyDPP)]4[OTf]8 (12). To a solution of 10.0 mg (0.012 mmol) of dpppPd(OTf)2, 7, in 5 mL of a 3:1 mixture of CHCl3 and CH3OH was added 7.5 mg (0.012 mmol) of porphyrin 3, and the resulting solution was stirred at room temperature for 1 h. The solvent was reduced in volume to 1 mL in vacuo and ether was added resulting in the formation of a dark-red solid, which was collected, washed with ether, and dried in vacuo. Yield 16.4 mg (94%). Mp 304-306 °C dec. 1H NMR (300 MHz, CDCl ) δ 9.62 (s, 16H, py H ), 8.93 (br, s, 8H, 3 R outer pyrrol Hβ), 8.33 (m, 16H, pyrrol Hβ), 8.12 (m, 36 H, py Hβ, porph outer Ph Ho,p, pyrrol Hβ), 7.68(m, 32H, PhP Ho), 7.65 (m, 56H, porph outer Ph Hm, PhP Hm,p), 6.98 (br, s, 8H, porph inner Ph Ho), 6.04 (br, s, 12H, porph inner Ph Hm,p), 3.50 (m, 16H, PhP-CH2), 2.56 (m, 8H, PhP-CH2CH2), -3.04 (s, 8H, NH). 13C{1H} NMR (125 MHz, CDCl3) δ 153.7 (s, py Cγ), 149.3 (s, py CR), 143.3 (s), 141.1 (s), 134.8 (s, py Cβ), 133.7 (m), 132.9 (s), 132.0 (s), 130.2 (s), 126.8 (s), 125.4 (m), 121.3 (q, J ) 318 Hz, CF3SO3), 114.8 (s, porph C-5 and C-15), 95.0 (s, porph C-10 and C-20), 29.9 (PhP CH2), 18.3 (s, PhPCH2CH2). 31 P{1H} NMR (121 MHz, CDCl3, H3PO4) δ 3.9 (s). 19F NMR (282 MHz, CDCl3, CFCl3) δ -79.6 (s). UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 268 (151 000), 422 (918 000), 520 (77 000), 556 (52 000), 594 (29 000), 650 (35 000). Anal. Calcd for C284H216N24P8O24S8F24Pd4‚ 8H2O: C, 58.02; H, 3.98; N, 5.72; S, 4.36. Found: C, 57.72; H, 3.92; N, 5.63; S, 4.48. [Pt(dppp)(trans-DPyDPP)]4[OTf]8 (13). A solution of 10.0 mg (0.011 mmol) of dpppPt(OTf)2, 8, in 5 mL of acetone was treated with 6.8 mg (0.011 mmol) of porphyrin 3 and the resulting solution was stirred at 40 °C for 4 h. The solvent was reduced in volume to 0.5 mL followed by addition of diethyl ether. The brown precipitate was collected, washed with ether, and dried in vacuo. Yield: 14.0 mg (83%). Mp 330-332 °C dec. 1H NMR (500 MHz, acetone-d6) δ 9.70 (d, J ) 4.5 Hz, 16H, py HR), 9.10 (s, 8H, outer pyrrol Hβ), 8.68 (s, 8H, outer pyrrol Hβ), 8.47 (s, 8H, inner pyrrol Hβ), 8.39 (m, 24H, porph outer Ph Ho, py Hβ), 8.30 (m, 32H, PhP Ho), 8.11 (s, 8H, inner pyrrol Hβ), 7.90 (m, 12H, porph outer Ph Hm,p), 7.75 (m, 48H, PhP Hm,p), 7.03 (s, 8H, porph inner Ph Hο), 6.12 (s, 12H, porph inner Ph Hm,p), 3.78 (s, 16H, PhP-CH2), 2.59 (m, 8H, PhP-CH2CH2), -3.03 (s, 8H, NH). 13C{1H} NMR (125 MHz, CDCl ) δ 154.3 (s, py C ), 149.4 (s, py C ), 3 γ R 141.9 (s), 134.7 (m), 133.8 (m), 132.9 (s), 132.5 (s), 130.1 (s), 127.3 (m), 121.3 (q, J ) 320 Hz, CF3SO3), 114.5 (s), 99.7 (s), 29.9 (PhP CH2), 18.4 (s, PhPCH2CH2). 31P{1H} NMR (202 MHz, acetone-d6, H3PO4) δ -9.9 (JPt-P ) 3060 Hz). 19F NMR (282 MHz, CDCl3, CFCl3) δ -78.9 (s). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 426 (1 000 000), 518 (52 000), 558 (36 000), 592 (18 000), 652 (18 000). Anal. Calcd for C284H216N24P8O24S8F24Pt4‚8H2O: C, 54.72; H, 3.75; N, 5.39; S, 4.11. Found: C, 54.47; H, 3.67; N, 5.14; S, 3.91. [Pd(dppp)(trans-ZnDPyDPP)]4[OTf]8 (14). To a solution of 8.6 mg (0.013 mmol) of 4 in 5 mL of CHCl3 was added 10.3 mg (0.013 mmol) of dpppPd(OTf)2, 7, and the solution was stirred at room temperature for 1 h. The solvent was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark-purple precipitate was filtered and dried in vacuo. Yield: 14.8 mg (78%). Mp 280-285 °C dec. 1H NMR (300 MHz, CDCl3/CD3OD) δ 9.41 (br, s, 8H, outer pyrrol Hβ), 9.33 (s, 16H, py HR), 8.76-8.64 (m, 8H, outer pyrrol Hβ), 8.25 (m, 16H, inner pyrrol Hβ), 8.02-7.86 (m, 28H, porph outer Ph Ho,p, py Hβ), 7.66-7.38 (m, 88H, porph outer Ph Hm, PhP Ho,m,p), 6.90

J. Am. Chem. Soc., Vol. 121, No. 12, 1999 2749 (br, s, 8H, porph inner Ph Ho), 5.95 (br, s, 12H, porph inner Ph Hm,p), 3.58 (s, 16H, PhP-CH2), 2.43 (m, 8H, PhP-CH2CH2). 13C{1H} NMR (125 MHz, CDCl3/CD3OD) δ 154.3 (s), 149.4 (s), 141.9 (s), 134.7 (m), 133.8 (m), 132.9 (s), 132.5 (s), 130.1 (s), 127.3 (m), 121.3 (q, J ) 320 Hz, CF3SO3), 114.5 (s), 99.7 (s), 29.9 (s), 18.4 (s). 31P{1H} NMR (121 MHz, CDCl3/CD3OD, H3PO4) δ 4.8 (s). 19F NMR (282 MHz, CDCl3/ CD3OD, CFCl3) δ -79.5 (s). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 429 (813 000), 557 (48 000), 608 (27 000). [Pt(dppp)(trans-ZnDPyDPP)]4[OTf]8 (15). A solution of 7.5 mg (0.011 mmol) of 4 and 10.0 mg (0.011 mmol) of dpppPt(OTf)2, 8 in 10 mL of a 3:1 mixture of CHCl3 and CH3OH was stirred at room temperature for 5 days. The solvent was reduced in volume, followed by addition of diethyl ether. The brown solid was collected, washed with ether, and dried in vacuo. Yield: 14.4 mg (82%). Mp 310-315 °C dec. 1H NMR (300 MHz, CDCl3/CD3OD) δ 9.41 (br, s, 8H, outer pyrrol Hβ), 9.33 (s, 16H, py HR), 8.76-8.64 (m, 8H, outer pyrrol Hβ), 8.25 (m, 16H, inner pyrrol Hβ), 8.02-7.86 (m, 28H, porph outer Ph Ho,p, py Hβ), 7.66-7.38 (m, 88H, porph outer Ph Hm, PhP Ho,m,p), 6.90 (br, s, 8H, porph inner Ph Ho), 5.95 (br, s, 12H, porph inner Ph Hm,p), 3.58 (16H, PhP-CH2), 2.43 (m, 8H, PhP-CH2CH2). 13C{1H} NMR (125 MHz, CDCl3/CD3OD) δ 154.3 (s), 149.4 (s), 141.9 (s), 134.7 (m), 133.8 (m), 132.9 (s), 132.5 (s), 130.1 (s), 127.3 (m), 121.3 (q, J ) 320 Hz, CF3SO3), 114.5 (s), 99.7 (s), 29.9 (s), 18.4 (s). 31P{1H} NMR (121 MHz, CDCl3/CD3OD, H3PO4) δ -7.8 (JPt-P ) 3043 Hz). 19F NMR (282 MHz, CDCl3/CD3OD, CFCl3) δ -74.5 (s). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 433 (1 040 000), 560 (58 000), 608 (39 000). [Pd(dppp)(trans-DPyTTP)]4[OTf]8 (16). To a solution of 15.0 mg (0.017 mmol) of porphyrin 5 in 10 mL of CH2Cl2 was added 14.0 mg (0.017 mmol) of dpppPd(OTf)2, 7, and the resulting solution was stirred at room temperature for 1 h. The solvent vas reduced in volume to 1 mL in vacuo and pentane was added resulting in the formation of a dark-red solid, which was collected, washed with pentane, and dried in vacuo. Yield 28.0 mg (96%). Mp 248-250 °C dec. 1H NMR (300 MHz, CD2Cl2, TMS) δ 10.29 (s, 4H, porph H-20), 9.77 (s, 4H, porph H-10), 9.55 (d, J ) 5.1 Hz, 16H, py HR), 8.15-8.10 (m, 48H, py Hβ, PhP Ho), 7.75-7.64 (m, 48H, PhP Ho+Hp), 3.99 (m, 16H, outer hexyl (CH2)(CH2)4CH3), 3.27 (m, 16H, PhP-CH2), 2.86 (m, 16H, inner hexyl (CH2)(CH2)4CH3), 2.51 (m, 8H, PhP-CH2CH2), 2.22 (m, 16H, outer hexyl CH2(CH2)(CH2)3CH3), 2.06 (m, 48H, porph-CH3), 1.80 (m, 16H, outer hexyl (CH2)2(CH2)(CH2)2CH3), 1.58 (m, 16H, outer hexyl (CH2)3(CH2)CH2CH3), 1.45 (m, 16H, outer hexyl (CH2)4CH2CH3), 1.15 (m, 16H, inner hexyl CH2(CH2)(CH2)3CH3), 0.97 (m, 24H, outer hexyl CH3), 0.12 (m, 16H, inner hexyl (CH2)2(CH2)(CH2)2CH3), -0.08 (m, 16H, inner hexyl (CH2)3(CH2)CH2CH3), -0.25 (m, 16H, inner hexyl (CH2)4CH2CH3), -0.51 (m, 24H, inner hexyl CH3), -2.38 (s, 8H, NH). 13C{1H} NMR (75 MHz, CD Cl , TMS) δ 154.5 (s, py C ), 151.1 (s, 2 2 γ py CR), 145.3 (s, porph C1), 145.2 (s, porph C9), 144.2 (s, porph C4, C6), 142.2 (s, porph C3, C7), 135.5 (s, porph C2), 134.7 (s, porph C8), 134.2 (s, py Cβ), 133.4 (s, PhP Co), 131.8 (s, PhP Cp), 130.8 (s, PhP Cm), 125.7 (m, PhP Cipso), 119.6 (q, J ) 319 Hz, CF3SO3), 113.0 (s, porph C5), 98.8 (s, porph C20), 98.4 (s, porph C10), 33.8 (s, outer hexyl CH2(CH2)4CH3), 32.6 (s, porph outer CH3), 31.1 (s, inner hexyl CH2(CH2)4CH3), 30.6 (s, porph inner CH3), 29.2, 27.2 (all s, outer hexyl), 26.4, 25.1, 24.9, 23.4 (all s, outer and inner hexyls), 22.0 (m, PhP CH2), 19.0 (s, PhPCH2CH2), 17.8, 17.1, 14.5, 13.1 (all s, inner hexyl). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ 6.4 (s). 19F NMR (282 MHz, CD2Cl2, CFCl3) δ -76.1 (s). IR (neat) 2926, 2863, 1608, 1438, 1252, 1155, 1030, 747 cm-1. UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 276 (574 000), 414 (634 000), 510 (67 000), 546 (39 000), 580 (36 000), 632 (20 000). Anal. Calcd for C348H408N24P8O24S8F24Pd4‚5H2O: C, 61.59; H, 6.21; N, 4.96; S, 3.77. Found: C, 61.29; H, 6.11; N, 4.97; S, 3.74. MS (ES) m/z 1525.3 (M - 4OTf)4+ calcd 1525.8. [Pt(dppp)(trans-DPyTTP)]4[OTf]8 (17). A solution of 9.5 mg (0.011 mmol) of porphyrin 5 in 10 mL of CH2Cl2 was treated with 10.0 mg (0.011 mmol) of dpppPt(OTf)2, 8, and stirred at room temperature for 4 days. The solvent was reduced in volume to 0.5 mL followed by addition of diethyl ether. The brown precipitate was collected, washed with ether, and dried in vacuo. Yield: 16.5 mg (85%). Mp 290-292 °C dec. 1H NMR (300 MHz, CD2Cl2, TMS) δ 10.28 (s, 4H, porph H-20), 9.77 (s, 4H, porph H-10), 9.65 (d, J ) 4.2 Hz, 16H, py HR), 8.17-8.12 (m, 48H, py Hβ, PhP Ho), 7.75 (t, J ) 6.9 Hz, 32H,

2750 J. Am. Chem. Soc., Vol. 121, No. 12, 1999 PhP Hm), 7.67 (t, J ) 7.5 Hz, 16H, PhP Hp), 3.99 (m, 16H, outer hexyl (CH2)(CH2)4CH3), 3.33 (m, 16H, PhP-CH2), 2.84 (m, 16H, inner hexyl (CH2)(CH2)4CH3), 2.46 (m, 8H, PhP-CH2CH2), 2.22 (m, 16H, outer hexyl CH2(CH2)(CH2)3CH3), 2.07 (s, 24H, porph outer CH3), 2.00 (s, 24H, porph inner CH3), 1.80 (m, 16H, outer hexyl (CH2)2(CH2)(CH2)2CH3), 1.56 (m, 16H, outer hexyl (CH2)3(CH2)CH2CH3), 1.46 (m, 16H, outer hexyl (CH2)4CH2CH3), 1.13 (m, 16H, inner hexyl CH2(CH2)(CH2)3CH3), 0.97 (m, 24H, outer hexyl CH3), 0.12 (m, 16H, inner hexyl (CH2)2(CH2)(CH2)2CH3), -0.08 (m, 16H, inner hexyl (CH2)3(CH2)CH2CH3), -0.24 (m, 16H, inner hexyl (CH2)4CH2CH3), -0.52 (m, 24H, inner hexyl CH3), -2.36 (s, 8H, NH). 13C{1H} NMR (75 MHz, CD2Cl2, TMS) δ 155.2 (s, py Cγ), 151.1 (s, py CR), 145.6 (s, porph C1), 145.4 (s, porph C9), 144.1 (s, porph C4, C6), 142.4 (s, porph C3), 142.2 (s, porph C7), 135.4 (s, porph C2), 134.6 (s, porph C8), 134.3 (s, py Cβ), 133.6 (s, PhP Co), 132.5 (s, PhP Cp), 130.7 (s, PhP Cm), 124.9 (m, PhP Cipso), 121.8 (q, J ) 320 Hz, CF3SO3), 112.7 (s, porph C5), 99.0 (s, porph C20), 98.5 (s, porph C10), 33.8 (s, outer hexyl CH2(CH2)4CH3), 32.6 (s, porph outer CH3), 31.1 (s, inner hexyl CH2(CH2)4CH3), 30.6 (s, porph inner CH3), 29.1, 27.2 (all s, outer hexyl), 26.3, 24.7, 23.3, 23.1 (all s, outer + inner hexyls), 21.9 (m, PhP CH2), 18.9 (s, PhPCH2CH2), 17.9, 17.1, 14.5, 13.1 (all s, inner hexyl). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ -16.0 (195Pt satellites, JPt-P ) 3101 Hz). 19F NMR (282 MHz, CD Cl , CFCl ) δ -76.5 (s). IR (neat) 2927, 2871, 2 2 3 1610, 1437, 1279, 1254, 1155, 1029, 748 cm-1. UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 416 (174 000), 512 (17 000), 548 (10 000), 578 (9000), 632 (5000). Anal. Calcd for C348H408N24P8O24S8F24Pt4‚7H2O: C, 58.22; H, 5.93; N, 4.69; S, 3.57. Found: C, 57.99; H, 5.74; N, 4.62; S, 3.50. [Pd(dppp)(trans-ZnDPyTTP)]4[OTf]8 (18). To a solution of 4.0 mg (0.0043 mmol) of 6 in 5 mL of CHCl3 was added 3.5 mg (0.0043 mmol) of dpppPd(OTf)2, 7, and the solution was stirred at room temperature for 1 h. The solvent was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark-purple precipitate was filtered and dried in vacuo. Yield: 7.4 mg (98%). Mp 224-226 °C dec. 1H NMR (500 MHz, CD2Cl2, TMS) δ 10.26 (s, 4H, porph H-20), 9.69 (s, 4H, porph H-10), 9.54 (d, J ) 5.0 Hz, 16H, py HR), 8.17-8.15 (m, 48Η, py Hβ, PhP Ho), 7.75 (t, J ) 7.3 Hz, 32H, PhP Hm), 7.69 (t, J ) 7.5 Hz, 16H, PhP Hp), 3.99 (m, 16H, outer hexyl (CH2)(CH2)4CH3), 3.25 (m, 16H, PhP-CH2), 2.74 (m, 16H, inner hexyl (CH2)(CH2)4CH3), 2.51 (m, 8H, PhP-CH2CH2), 2.22 (m, 16H, outer hexyl CH2(CH2)(CH2)3CH3), 2.08 (s, 24H, outer porph-CH3), 1.97 (s, 24H, inner porph-CH3), 1.81 (m, 16H, outer hexyl (CH2)2(CH2)(CH2)2CH3), 1.59 (m, 16H, outer hexyl (CH2)3(CH2)CH2CH3), 1.47 (m, 16H, outer hexyl (CH2)4CH2CH3), 1.28 (m, 16H, inner hexyl CH2(CH2)(CH2)3CH3), 0.98 (m, 24H, outer hexyl CH3), -0.02 (m, 16H, inner hexyl (CH2)2(CH2)(CH2)2CH3), -0.19 (m, 16H, inner hexyl (CH2)3(CH2)CH2CH3), -0.28 (m, 16H, inner hexyl (CH2)4CH2CH3), -0.55 (m, 24H, inner hexyl CH3). 13C{1H} NMR (125 MHz, CD2Cl2, TMS) δ 156.1 (s, py Cγ), 151.1 (s, py CR), 147.3 (s, porph C1, C9), 146.7 (s, porph C4, C6), 145.6 (s, porph C3), 145.4 (s, porph C7), 137.2 (s, porph C2), 136.7 (s, porph C8), 134.3 (s, py Cβ), 133.5 (s, PhP Co), 132.2 (s, PhP Cp), 130.9 (s, PhP Cm), 125.8 (t, J ) 26.6 Hz, PhP Cipso), 121.8 (q, J ) 320 Hz, CF3SO3), 114.7 (s, porph C5), 99.4 (s, porph C20), 99.0 (s, porph C10), 33.8 (s, outer hexyl CH2(CH2)4CH3), 32.5 (s, porph outer CH3), 30.9 (s, inner hexyl CH2(CH2)4CH3), 30.6 (s, porph inner CH3), 30.3, 29.2 (all s, outer hexyl), 27.2, 26.2, 25.2, 23.4 (all s, outer + inner hexyls), 22.0 (m, PhPCH2), 19.0 (s, PhPCH2CH2), 18.5, 18.2, 14.5, 13.1 (all s, inner hexyl). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ 9.0 (s). 19F NMR (282 MHz, CD2Cl2, CFCl3) δ -74.7 (s). IR (neat) 3107, 2925, 1606, 1436, 1260, 1101, 1029, 801 cm-1. UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 348 (51 000), 414 (397 000), 542 (35 000), 582 (29 000). Anal. Calcd for C348H400N24P8O24S8F24Pd4Zn4‚15H2O: C, 57.89; H, 6.00; N, 4.66; S, 3.55. Found: C, 57.66; H, 5.80; N, 4.83; S, 3.49. [Pt(dppp)(trans-ZnDPyTTP)]4[OTf]8 (19). A solution of 16.0 mg (0.017 mmol) of 6 and 15.7 mg (0.017 mmol) of dpppPt(OTf)2, 8, in 5 mL of CHCl3 was stirred at room temperature for 5 days. The solvent was reduced in volume, followed by addition of diethyl ether. The brown solid was collected, washed with ether, and dried in vacuo. Yield: 25.4 mg (80%). Mp 260-262 °C dec. 1H NMR (500 MHz, CD2Cl2, TMS) δ 10.22 (s, 4H, porph H-20), 9.98 (s, 4H, porph H-10),

Fan et al. 9.70 (d, J ) 5.4 Hz, 16H, py HR), 8.18 (m, 48Η, py Hβ, PhP Ho), 7.78 (t, J ) 7.2 Hz, 32H, PhP Hm), 7.65 (t, J ) 7.2 Hz, 16H, PhP Hp), 3.96 (m, 16H, outer hexyl (CH2)(CH2)4CH3), 3.36 (m, 16H, PhP-CH2), 2.84 (m, 16H, inner hexyl (CH2)(CH2)4CH3), 2.50 (m, 8H, PhP-CH2CH2), 2.19 (m, 16H, outer hexyl CH2(CH2)(CH2)3CH3), 2.06 (s, 24H, outer porph-CH3), 1.97 (s, 24H, inner porph-CH3), 1.78 (m, 16H, outer hexyl (CH2)2(CH2)(CH2)2CH3), 1.57 (m, 16H, outer hexyl (CH2)3(CH2)CH2CH3), 1.46 (m, 16H, outer hexyl (CH2)4CH2CH3), 1.02 (m, 16H, inner hexyl CH2(CH2)(CH2)3CH3), 1.00 (m, 24H, outer hexyl CH3), 0.00 (m, 16H, inner hexyl (CH2)2(CH2)(CH2)2CH3), -0.21 (m, 32H, inner hexyl (CH2)3CH2CH2CH3), -0.50 (m, 24H, inner hexyl CH3). 13C{1H} NMR (125 MHz, CDCl3, TMS) δ 156.5 (s, py Cγ), 150.7 (s, py CR), 147.0 (s, porph C1, C9), 146.2 (s, porph C4, C6), 145.5 (s, porph C3), 145.0 (s, porph C7), 136.5 (s, porph C2), 136.0 (s, porph C8), 134.0 (s, py Cβ), 133.2 (s, PhP Co), 132.4 (s, PhP Cp), 130.5 (s, PhP Cm), 124.6 (t, J ) 34.9 Hz, PhP Cipso), 121.4 (q, J ) 318 Hz, CF3SO3), 113.7 (s, porph C5), 99.3 (s, porph C20), 98.8 (s, porph C10), 33.5 (s, outer hexyl CH2(CH2)4CH3), 32.2 (s, porph outer CH3), 32.1 (s, inner hexyl CH2(CH2)4CH3), 30.6 (s, porph inner CH3), 30.3, 28.8 (all s, outer hexyl), 27.0, 25.9, 24.8, 23.0 (all s, outer + inner hexyls), 21.6 (m, PhP CH2), 18.7 (s, PhPCH2CH2), 18.3, 18.0, 14.4, 13.0 (all s, inner hexyl). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ -14.1 (s, 195Pt satellites, JPt-P ) 3086 Hz). 19F NMR (282 MHz, CD2Cl2, CFCl3) δ -75.9 (s). IR (neat) 2963, 2927, 2884, 1608, 1439, 1291, 1151, 1031, 699 cm-1. UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 350 (81 000), 420 (492 000), 546 (48 000), 584 (34 000). Anal. Calcd for C348H400N24P8O24S8F24Pt4Zn4‚8H2O: C, 56.11; H, 5.63; N, 4.51; S, 3.44. Found: C, 55.91; H, 5.77; N, 4.44; S, 3.50. [Pd(dppp)(cis-DPyDPP)]2[OTf]4 (20). To a solution of 10.0 mg (0.012 mmol) of dpppPd(OTf)2, 7, in 2 mL of a 3:1 mixture of CHCl3 and CH3OH was added 7.5 mg (0.012 mmol) of porphyrin 1 and the resulting solution was stirred at room temperature for 1 h. The solvent was reduced in volume to 1 mL in vacuo and ether was added resulting in the formation of a dark-red solid, which was collected, washed with ether, and dried in vacuo. Yield 16.3 mg (93%). Mp 338-340 °C dec. 1H NMR (500 MHz, CDCl ) δ 9.83 (d, J ) 6.0 Hz, 8H, py H ), 8.92 3 R (d, J ) 4.5 Hz, 4H, porph H-2 and H-13), 8.86 (s, 4H, porph H-17 and H-18), 8.58 (s, 4Η, porph H-7 and H-8), 8.33 (d, J ) 4.5 Hz, 4H, porph H-3 and H-12), 8.23-8.17 (m, 16H, py Hβ, porph-Ph Ho), 8.07 (m, 16H, PhP Ho), 7.82 (m, 12H, porph-Ph Hm + Hp), 7.66 (m, 16H, PhP Hm), 7.51 (m, 8H, PhP Hp), 3.49 (m, 8H, PhP-CH2), 2.53 (m, 4H, PhP-CH2CH2), -3.00 (s, 4H, NH). 13C{1H} NMR (125 MHz, CDCl3) δ 153.3 (s, py Cγ), 149.3 (s, py CR), 141.6 (s, porph C17,18), 134.9 (s, py Cβ), 133.7 (s), 132.9 (s), 130.2 (s), 128.4 (s), 127.1 (s), 125.7 (m), 122.7 (s), 121.3 (q, J ) 318 Hz, CF3SO3), 114.7 (s), 29.9 (PhP CH2), 18.3 (s, PhPCH2CH2). 31P{1H} NMR (202 MHz, CDCl3, H3PO4) δ 4.4 (s). 19F NMR (282 MHz, CDCl3, CFCl3) δ -79.4 (s). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 268 (72 000), 422 (485 000), 520 (33 000), 556 (17 000), 592 (12 000), 650 (6000). Anal. Calcd for C142H108N12P4O12S4F12Pd2‚5H2O: C, 57.67; H, 4.02; N, 5.68; S, 4.34. Found: C, 57.51; H, 3.99; N, 5.40; S, 4.37. MS (FAB) m/z 2716.5 (M - OTf)+ calcd 2717.4. [Pt(dppp)(cis-DPyDPP)]2[OTf]4 (21). A solution of 7.3 mg (0.0081 mmol) of dpppPt(OTf)2, 8, in 2 mL of a 3:1 mixture of CHCl3 and CH3OH was treated with 5.0 mg (0.0081 mmol) of porphyrin 1 and stirred at room temperature for 2 days. The solvent was reduced in volume to 0.5 mL followed by addition of diethyl ether. The brown precipitate was collected, washed with ether, and dried in vacuo. Yield: 9.0 mg (73%). Mp 383-385 °C dec. 1H NMR (300 MHz, CDCl3) δ 9.88 (d, J ) 4.2 Hz, 8H, py HR), 8.92 (d, J ) 4.8 Hz, 4H, porph H-2 and H-13), 8.85 (s, 4H, porph H-17 and H-18), 8.57 (s, 4Η, porph H-7 and H-8), 8.31 (d, J ) 4.8 Hz, 4H, porph H-3 and H-12), 8.21(m, 16H, py Hβ, porph-Ph Ho), 8.09 (m, 16H, PhP Ho), 7.82 (m, 12H, porph-Ph Hm + Hp), 7.66 (m, 16H, PhP Hm), 7.49 (m, 8H, PhP Hp), 3.57 (8H, PhP-CH2), 2.49 (m, 4H, PhP-CH2CH2), -2.99 (s, 4H, NH). 13C{1H} NMR (125 MHz, CDCl3) δ 153.8 (s, py Cγ), 149.4 (s, py CR), 141.5 (s, porph C17,18), 134.9 (s), 134.7 (s), 133.7 (s), 133.5 (s, py Cβ), 133.0 (s), 130.1 (s), 128.4 (s), 127.1 (s), 125.0 (m), 123.0 (s), 121.3 (q, J ) 320 Hz, CF3SO3), 114.4 (s), 29.9 (PhP CH2), 18.4 (s, PhPCH2CH2). 31P{1H} NMR (121 MHz, CDCl3, H3PO4) δ -16.9 (s, 195Pt satellites, J 19F NMR (282 MHz, CDCl , Pt-P ) 3069 Hz). 3

Self-Assembly of Porphyrin Arrays CFCl3) δ -79.4 (s). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 422 (453 000), 520 (30 000), 556 (15 000), 594 (10 000), 650 (5000). Anal. Calcd for C142H108N12P4O12S4F12Pt2‚6H2O: C, 54.10; H, 3.84; N, 5.33; S, 4.07. Found: C, 54.03; H, 3.68; N, 5.15; S, 4.03. MS (FAB) m/z 2895.8 (M - OTf)+ calcd 2895.6. [Pd(dppp)(cis-ZnDPyDPP)]2[OTf]4 (22). A solution of 8.3 mg (0.012 mmol) of 2 in 3 mL of CHCl3 was added to 10.0 mg (0.012 mmol) of dpppPd(OTf)2, 7, in 5 mL of a 3:1 mixture of CHCl3 and CH3OH. The resulting solution was stirred at room temperature for 1 h. The solvent was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark-purple precipitate was filtered and dried in vacuo. Yield: 17.1 mg (93%). Mp 320-325 °C dec. 1H NMR (300 MHz, CDCl3/CD3OD) δ 9.52 (d, J ) 4.5 Hz, 8H, py HR), 8.83 (d, J ) 4.8 Hz, 4H, porph H-2 and H-13), 8.77 (s, 4H, porph H-17 and H-18), 8.56 (s, 4Η, porph H-7 and H-8), 8.22 (d, J ) 4.8 Hz, 4H, porph H-3 and H-12), 8.11-8.05 (m, 16H, py Hβ, porph-Ph Ho), 7.94 (m, 16H, PhP Ho), 7.69 (m, 12H, porph-Ph Hm + Hp), 7.55 (m, 16H, PhP Hm), 7.45 (m, 8H, PhP Hp), 3.32 (8H, PhP-CH2), 2.41 (m, 4H, PhP-CH2CH2). 13C{1H} NMR (125 MHz, CDCl3) δ 154.4 (s), 150.7 (d, J ) 31 Hz), 148.6 (s), 148.4 (s), 142.9 (s), 134.8 (s), 132.8 (m), 131.0 (d, J ) 21 Hz), 130.0 (s), 129.3 (s), 127.8 (s), 126.7 (s), 125.3 (m), 123.0 (s), 120.6 (q, J ) 320 Hz, CF3SO3), 115.3 (s), 29.9 (PhP CH2), 18.1 (s, PhPCH2CH2). 31P{1H} NMR (121 MHz, CDCl3/CD3OD, H3PO4) δ 5.0 (s). 19F NMR (282 MHz, CDCl3, CFCl3) δ -79.3 (s). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 264 (74 000), 318 (51 000), 430 (469 000), 562 (40 000), 604 (18 000). Anal. Calcd for C142H104N12P4O12S4F12Pd2Zn2‚6H2O: C, 54.98; H, 3.77; N, 5.42; S, 4.13. Found: C, 54.91; H, 3.77; N, 5.21; S, 3.76. [Pt(dppp)(cis-ZnDPyDPP)]2[OTf]4 (23). A solution of 5.1 mg (0.0075 mmol) of 2 in 1 mL of CHCl3 was added to 6.8 mg (0.0075 mmol) of dpppPt(OTf)2, 8, in 2 mL of a 3:1 mixture of CHCl3 and CH3OH. The resulting solution was stirred at room temperature for 1 day. The solvent was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark-purple precipitate was filtered and dried in vacuo. Yield: 9.7 mg (82%). Mp 353-355 °C dec. 1H NMR (500 MHz, CDCl3/CD3OD) δ 9.55 (br, s, 8H, py HR), 8.84 (d, J ) 4.5 Hz, 4H, porph H-2 and H-13), 8.78 (s, 4H, porph H-17 and H-18), 8.58 (s, 4Η, porph H-7 and H-8), 8.21 (d, J ) 4.5 Hz, 4H, porph H-3 and H-12), 8.10 (m, 16H, py Hβ, porph-Ph Ho), 7.96 (m, 16H, PhP Ho), 7.68 (m, 12H, porph-Ph Hm + Hp), 7.56 (m, 16H, PhP Hm), 7.45 (m, 8H, PhP Hp), 3.50 (8H, PhP-CH2), 2.37 (m, 4H, PhP-CH2CH2). 13C{1H} NMR (125 MHz, CDCl /CD OD) δ 155.7 (s, py C ), 151.0 3 3 γ (s, py CR), 150.3 (s), 148.3 (s), 147.9 (s), 142.7 (s), 134.7 (s), 133.5 (s), 133.0 (m), 132.7 (s), 130.8 (s), 130.0 (s), 127.8 (s), 126.6 (s), 124.8 (m), 123.3 (s), 121.0 (q, J ) 320 Hz, CF3SO3), 114.4 (s), 29.8 (PhP CH2), 18.2 (s, PhPCH2CH2). 31P{1H} NMR (121 MHz, CDCl3/CD3OD, H3PO4) δ -16.7 (s, 195Pt satellites, JPt-P ) 3025 Hz). 19F NMR (282 MHz, CDCl3, CFCl3) δ -79.4 (s). UV-vis (CHCl3) λmax () [nm (cm-1 M-1)] 318 (14 000), 434 (186 000), 562 (15 000), 604 (6000). Anal. Calcd for C142H104N12P4O12S4F12Pt2Zn2‚6H2O C, 52.01; H, 3.57; N, 5.13; S, 3.91. Found: C, 51.75; H, 3.67; N, 4.89; S, 3.54. Cyclotetrakis[(cis-DPyDPP)[1,4-bis(trans-Pt(PEt 3 ) 2 (OTf))benzene]] (24). To a solution of 10.0 mg (0.0081 mmol) of 1,4-bis(trans-Pt(PEt3)2(OTf))benzene, 11, in 2 mL of CH2Cl2 was added 5.0 mg (0.0081 mmol) compound 1. The resulting solution was stirred at room temperature for 1 h. The solvent was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark-purple precipitate was filtered and dried in vacuo. Yield: 14.3 mg (95%). Mp 220-225 °C dec. 1H NMR (500 MHz, CD2Cl2) δ 9.22 (s, 16H, py HR), 9.10 (s, 8H, porph H-2 and H-13), 9.04 (s, 8H, porph H-17 and H-18), 8.98 (s, 8Η, porph H-7 and H-8), 8.78 (s, 8H, porph H-3 and H-12), 8.64 (s, 16H, py Hβ), 8.27 (m, 16H, porph-Ph Ho), 7.85 (m, 24H, porph-Ph Hm + Hp), 7.31 (m, 16H, PhPt Ho), 1.71 (m, 96H, PCH2CH3), 1.39 (m, 144H, PCH2CH3), -2.77 (s, 8H, NH). 13C{1H} NMR (125 MHz, CD2Cl2) δ 154.1 (s, py Cγ), 151.1 (s, py CR), 141.9 (s), 137.3 (s), 135.2 (s), 133.7 (s), 131.3 (m), 128.8 (s), 127.5 (s), 125.5 (s), 123.4 (s), 121.7 (q, J ) 319 Hz, CF3SO3), 114.9 (s), 13.4 (PCH2CH3), 8.3 (s, PCH2CH3). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ 17.4 (JPt-P ) 2721 Hz). 19F NMR (282 MHz, CD2Cl2, CFCl3) δ -73.5 (s). UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 298 (84 000), 372 (113 000), 424 (1 258 000), 518 (82 000), 556 48 000), 594

J. Am. Chem. Soc., Vol. 121, No. 12, 1999 2751 (30 000), 650 (25 000). Anal. Calcd for C296H368N24P16O24S8F24Pt8: C, 47.95; H, 5.00; N, 4.53; S, 3.46. Found: C, 48.02; H, 5.11; N, 4.39; S, 3.26. Cyclotetrakis[(cis-ZnDPyDPP)[1,4-bis(trans-Pt(PEt3)2(OTf))benzene]] (25). To a solution of 10.0 mg (0.0081 mmol) of 1,4-bis(trans-Pt(PEt3)2(OTf))benzene, 11, in 2 mL of CH2Cl2 was added 5.5 mg (0.0081 mmol) of compound 2. The resulting solution was stirred at 40 °C for 10 h. The solvent was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark-red precipitate was filtered and dried in vacuo. Yield: 13.2 mg (85%). Mp 262-264 °C dec. 1H NMR (300 MHz, CD2Cl2) δ 9.07 (m, 24H, py HR, porph H-2 and H-13), 8.97 (s, 8H, porph H-17 and H-18), 8.93 (d, J ) 4.8 Hz, 8H, porph H-7 and H-8), 8.80 (d, J ) 4.2 Hz, 8Η, porph H-3 and H-12), 8.62 (m, 16H, py Hβ), 8.27 (m, 16H, porph-Ph Ho), 7.81 (m, 24H, porph-Ph Hm + Hp), 7.29 (m, 16H, PhPt Ho), 1.70 (m, 96H, PCH2CH3), 1.39 (m, 144H, PCH2CH3). 13C{1H} NMR (125 MHz, CD2Cl2) δ 156.2 (s), 151.6 (s), 151.0 (s), 150.2 (s), 149.0 (s), 148.7 (s), 143.2 (s), 137.3 (s), 135.1 (s), 133.9 (s), 133.5 (s), 133.2 (s), 131.6 (s), 130.4 (m), 128.1 (s), 127.0 (s), 125.6 (s), 123.7 (s), 120.6 (q, J ) 319 Hz, CF3SO3), 115.1 (s), 13.4 (PCH2CH3), 8.3 (s, PCH2CH3). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ 17.4 (JPt-P ) 2732 Hz). 19F NMR (282 MHz, CD2Cl2, CFCl3) δ -74.3 (s). UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 314 (90 000), 432 (1 068 000), 560 (82 000), 602 (31 000). Anal. Calcd for C296H360N24P16O24S8F24Pt8Zn4‚20H2O: C, 44.28; H, 5.02; N, 4.19; S, 3.19. Found: C, 44.16; H, 4.78; N, 3.89; S, 3.39. Cyclotetrakis[[cis-Pd(R(+)-BINAP)(OTf)2](trans-DPyDPP)] (26). To a solution of 10.0 mg (0.0097 mmol) of Pd(R(+)-BINAP)(OTf)2, 9, in 5 mL of CH2Cl2 was added 6.0 mg (0.0097 mmol) of trans-DPyDPP, 3. The resulting solution was stirred at room temperature for 20 min and was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark brown precipitate was filtered and dried in vacuo. Yield: 14.1 mg (88%). Mp 268-270 °C dec. [R]D +500° (c 3.6 × 10-5 M, CH2Cl2, 20 °C). CD (CH2Cl2) λ (∆) [nm (L mol-1 cm-1)] 251 (+416.7), 276 (-20.8), 332 (+166.7), 351 (-104.2), 422 (-975.0), 432 (+833.3). 1H NMR (300 MHz, CD2Cl2) δ 9.34 (s, 8H, py HR), 9.18 (s, 8H, py HR), 8.94 (d, J ) 4.2 Hz, 4H), 8.84 (s, 4H), 8.63 (m, 8H), 8.39-8.16 (m, 40H), 8.10 (s, 4H), 8.02 (d, J ) 8.4 Hz, 16H), 7.90 (m, 24H), 7.80 (m, 24H), 7.68 (d, J ) 6.0 Hz, 8H), 7.52 (m, 24H), 7.36 (m, 4H), 7.14 (m, 32H), 6.59 (d, J ) 8.4 Hz, 16H), 6.18 (m, 8H), -3.24 (s, 4H, NH), -3.33 (s, 4H, NH). 13C{1H} NMR (125 MHz, CD2Cl2) δ 154.2 (d, J ) 27 Hz), 150.5 (m), 142.1 (s), 141.6 (s), 140.7 (m), 137.4 (m), 136.2 (s), 135.5 (s), 135.0 (d, J ) 28 Hz), 133.8 (s), 133.0 (s), 132.3 (s), 131.8 (m), 131.4 (s), 130.9 (s), 130.0 (s), 129.4 (s), 129.0 (s), 128.1 (m), 127.8 (m), 127.6 (s), 127.2 (s), 126.1 (m), 125.2 (s), 124.7 (s), 121.9 (d, J ) 34 Hz), 121.7 (q, J ) 339 Hz, CF3SO3), 119.6 (s), 119.1 (s), 115.2 (d, J ) 49 Hz). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ 24.5 (AB, J ) 18 Hz), 25.0 (AB, J ) 18 Hz). 19F NMR (282 MHz, CD2Cl2, CFCl3) δ -77.6 (s). UVvis (CH2Cl2) λmax () [nm (cm-1 M-1)] 290 (246 000), 422 (1 641 000), 518 (100 000), 556 (63 000), 592(31 000), 648 (33 000). Anal. Calcd for C352H240N24P8O24S8F24Pd4‚8H2O: C, 62.92; H, 3.84; N, 5.00; S, 3.82. Found: C, 62.76; H, 3.93; N, 5.06; S, 3.81. Cyclotetrakis[[cis-Pd(S(-)-BINAP)(OTf)2](trans-DPyDPP)] (27). To a solution of 10.0 mg (0.0097 mmol) of Pd(S(-)-BINAP)(OTf)2, 10, in 5 mL of CH2Cl2 was added 6.0 mg (0.0097 mmol) of transDPyDPP, 3. The resulting solution was stirred at room temperature for 20 min and was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark brown precipitate was filtered and dried in vacuo. Yield: 15.1 mg (94%). Mp 268-270 °C dec. [R]D -474° (c 2.8 × 10-5 M, CH2Cl2, 20 °C). CD (CH2Cl2) λ (∆) [nm (L mol-1 cm-1)] 251 (-387.5), 276 (+93.8), 332 (-125.0), 351 (+120.8), 422 (+843.8), 432 (-645.8). UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)] 292 (232 000), 422 (1 647 000), 518 (94 000), 554 (57 000), 592 (26 000), 648 (28 000). 1H, 31P, 13C, and 19F NMR spectra of 27 were found to be identical with those of 26. Anal. Calcd for C352H240N24P8O24S8F24Pd4‚8H2O: C, 62.92; H, 3.84; N, 5.00; S, 3.82. Found: C, 62.76; H, 3.93; N, 5.06; S, 3.81. Cyclotetrakis[[cis-Pd(R(+)-BINAP)(OTf)2](trans-ZnDPyDPP)] (28). To a solution of 7.6 mg (0.0074 mmol) of Pd(R(+)-BINAP)(OTf)2, 9, in 5 mL of CHCl3 was added 5.0 mg (0.0074 mmol) of trans-

2752 J. Am. Chem. Soc., Vol. 121, No. 12, 1999 ZnDPyDPP, 4, in a 3:1 mixture of chloroform and methanol. The resulting solution was stirred at room temperature for 40 min and was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark brown precipitate was filtered and dried in vacuo. Yield: 10.1 mg (80%). Mp 298-300 °C dec. CD (CH2Cl2) λ (∆) [nm (L mol-1 cm-1)], 233 (-300.5), 253 (+333.8), 286 (-115.0), 325 (+89.8), 339 (+23.8), 368 (+84.5). 1H NMR (300 MHz, CD2Cl2) δ 9.34 (s, 8H, py HR), 9.18 (s, 8H, py HR), 8.94 (d, J ) 4.2 Hz, 4H), 8.83 (s, 4H), 8.59 (m, 8H), 8.38-8.16 (m, 40H), 8.09 (s, 4H), 8.02 (d, J ) 8.4 Hz, 16H), 7.90 (m, 24Η), 7.80 (m, 24H), 7.68 (d, J ) 6.0 Hz, 8H), 7.52 (m, 24H), 7.36 (m, 4H), 7.14 (m, 32H), 6.59 (d, J ) 8.4 Hz, 16H), 6.17 (m, 8H). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ 25.8 (AB, J ) 18 Hz), 26.2 (AB, J ) 18 Hz). 19F NMR (282 MHz, CD2Cl2, CFCl3) δ -77.7 (s). UV-vis (CH2Cl2/CH3OH) λmax () [nm (cm-1 M-1)] 402 (180 000), 424 (1 740 000), 556 (94 000), 555 (34 000). Cyclobis[[cis-Pd(R(+)-BINAP)(OTf)2](cis-DPyDPP)] (29). To a solution of 16.6 mg (0.016 mmol) of Pd(R(+)-BINAP)(OTf)2, 9, in 10 mL of CH2Cl2 was added 10.0 mg (0.016 mmol) of cis-DPyDPP, 1. The resulting solution was stirred at room temperature for 20 min and was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark brown precipitate was filtered and dried in vacuo. Yield: 23.5 mg (88%). Mp 278-280 °C dec. [R]D +1090° (c 3.6 × 10-5 M, CH2Cl2, 20 °C). CD (CH2Cl2) λ (∆) [nm (L mol-1 cm-1)] 250 (+122.4), 276 (-65.3), 332 (+49.0), 351 (-62.0), 422 (+293.9). 1H NMR (300 MHz, CD Cl ) δ 9.64 (d, J ) 4.8 Hz, 4H, py H ), 9.58 2 2 R (d, J ) 4.8 Hz, 4H, py HR), 8.89 (s, 12H), 8.40 (m, 8H), 8.25-8.07 (m, 20H), 7.99-7.91 (m, 8H), 7.82-7.74 (m, 24H), 7.51 (q, J ) 7.5 Hz, 12Η), 7.32 (s, 4H), 7.13 (q, J ) 7.8 Hz, 12H), 6.60 (d, J ) 9.0 Hz, 8H), -2.96 (s, 4H, NH). 13C{1H} NMR (125 MHz, CD2Cl2) δ 154.2 (s), 151.1 (s), 150.1 (s), 142.0 (s), 140.8 (s), 136.0 (s), 135.4 (d, J ) 12 Hz), 135.1 (s), 133.8 (s), 133.4 (s), 132.7 (s), 132.5 (s), 132.3

Fan et al. (s), 130.9 (s), 130.1 (s), 129.3 (s), 129.0 (s), 128.6 (s), 128.3 (s), 127.7 (d, J ) 11 Hz), 127.4 (s), 125.8 (s), 125.3 (m), 124.7 (s), 122.9 (s), 121.5 (q, J ) 319 Hz, CF3SO3), 119.7 (s), 119.2 (m), 114.9 (s). 31P{1H} NMR (121 MHz, CD2Cl2, H3PO4) δ 27.3 (s). 19F NMR (282 MHz, CD2Cl2) δ -73.6 (s). UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)], 292 (95 000), 424 (642 000), 520 (39 000), 556 (20 000), 592(13 000), 648 (6000) nm. Anal. Calcd for C176H120N12P4O12S4F12Pd2‚8H2O: C, 61.59; H, 3.99; N, 4.90; S, 3.74. Found: C, 61.35; H, 3.76; N, 4.57; S, 3.79. Cyclobis[[cis-Pd(S(-)-BINAP)(OTf)2](cis-DPyDPP)] (30). To a solution of 16.6 mg (0.016 mmol) Pd(S(-)-BINAP)(OTf)2, 10, in 10 mL of CH2Cl2 was added 10.0 mg (0.016 mmol) of cis-DPyDPP, 1. The resulting solution was stirred at room temperature for 20 min and was reduced in volume to 0.5 mL in vacuo. Diethyl ether was then added and the dark brown precipitate was filtered and dried in vacuo. Yield: 24.9 mg (94%). Mp 278-280 °C dec. [R]D -1160° (c 5.4 × 10-5 M, CH2Cl2, 20 °C). CD (CH2Cl2) λ (∆) [nm (L mol-1 cm-1)], 250 (-81.6), 276 (+63.7), 332 (-40.8), 351 (+57.1), 422 (-302.0). UV-vis (CH2Cl2) λmax () [nm (cm-1 M-1)], 288 (100 000), 424 (638 000), 518 (42 000), 554 (21 000), 590(15 000), 646 (7000). 1H, 31P, 13C, and 19F NMR spectra of 30 were found to be identical with those of 29. Anal. Calcd for C176H120N12P4O12S4F12Pd2‚8H2O: C, 61.59; H, 3.99; N, 4.90; S, 3.74. Found: C, 61.35; H, 3.76; N, 4.57; S, 3.79.

Acknowledgment. Dedicated to Professor Allen J. Bard on the occasion of his 65th birthday. We thank the National Science Foundation (CHE-9529093) and the National Institute of Health (5R01GM57052) for financial support. JA9839825